When a plurality of data items composed of video and audio data are reproduced from a recording medium where they are recorded, it is necessary to carry out at high speed the processes of determining where to read an AV stream from, of decoding what has been read, and of searching for relevant marks. To date, such processes are performed illustratively by resorting to the following method (e.g., refer to Japanese Patent Laid-open No. 2002-158971):
The method involves managing an actual content stream using clip information while controlling reproduction of the AV stream based on play lists. As attribute information about the AV stream, address information “SPN_ATS_start, SPN_STC_start” about discontinuities in the AV stream is recorded to the clip information, together with information “EP_map, TU_map” associating time information with address information in the AV stream, as well as time information clip marks for characteristic pictures in the AV stream.
A typical recording medium carrying the above-mentioned plurality of data items formed by video and audio data is DVD-Video (digital versatile disk-video). The DVD-Video format includes specifications regarding multi-angle reproduction. Over a reproduction segment in which multi-angle reproduction is available, the user can select a desired angle for reproduction. In such a case, angles can be changed in seamless fashion by the recording/reproducing apparatus in use.
FIG. 1 is an explanatory view of a multi-angle format for DVD-Video. A multi-angle reproduction segment is made up of a plurality of subordinate reproduction segments called a cell each. In the example of FIG. 1, the multi-angle reproduction segment is formed by three cells #i+1 through #i+3 for angles #1 through #3 respectively. Actual AV stream data corresponding to the cells is called VOB's (video objects).
FIG. 2 is an explanatory view of an interleaved block structure for implementing multi-angle reproduction of DVD-Video. An interleaved block is constituted by a plurality of interleaved units (ILVU's). The VOB's corresponding to the cells making up a multi-angle reproduction segment are divided into ILVU's. The multiple VOB's constituting the multi-angle reproduction segment are multiplexed in increments of ILVU's. Each ILVU begins with a closed GOP (group of pictures).
The reproduction of DVD-Video with seamless angle change takes place illustratively as follows: suppose that the user changes reproduction paths from angle 2 to angle 1 to angle 3. In that case, the recording/reproducing apparatus jumps over the disk as shown in FIG. 3 so as to read data from ILVU1, ILVU2 and ILVU3 successively for reproduction. Each ILVU starts with DSI (data search information) which has an address of the destination ILVU to which to jump for the next angle.
When the AV stream is laid out as shown in FIG. 3, a jump occurs at every ILVU even when reproduction is continued at angle A. The frequent jumps can make reproduction unstable. Because the AV stream is laid out in such a fragmented manner on the recording medium, the amount of AV stream layout information is bound to increase.